The present invention relates in general to a prosthesis and more specifically to a composite socket which contains inflatable means.
Artificial limbs are usually provided with a socket into which the stump of a residual member is inserted. In the case of the below-knee amputee, for example, the function of the socket is to provide a weight bearing surface for the stump. The socket also functions to supply lateral support to the stump to maintain stability for the wearer, and is usually attached to an artificial limb that consists of a shin and ankle/foot section that completes the limb.
One of the most common problems amputees face on a daily basis is adjusting the fit of the socket to their ongoing needs. It is recognized that there is often a change in the volume of residual limb which may be slightly perceptible or significant depending on the situation. These volume changes cannot be completely accounted for or anticipated when making the socket because to a certain extent the human body is partially made of fluids. A majority of amputees have been the victims of diseases that effect the vascular system such as diabetes, and this vascular disease accounts for more amputations than any other single cause. The wearing of a prosthesis, with comfort, for members of this group can be especially difficult. The fluid volume within the body is dynamic, and can change in amounts as the person ages, but it also changes on a day-to-day basis.
The standard way for an amputee to adjust the fit of their below-knee socket is by wearing a stump sock(s). These socks are made from a variety of materials such as wool and cotton. The socks come in various thicknesses from one ply to eight plys of thickness of material. When the amputee feels the need, he may add or remove socks of various plys to adjust the fit of his socket. One difficulty associated with this technique is that the sock fits over the entire residual limb. Therefore, increasing the thickness of the plys can also increase the pressures over areas of the residual limb where it is not wanted. This can result in an increase of pressure over boney prominences of the below-knee residual limb.
It can therefore be seen that while adding and subtracting stump socks can solve some wearing problems, it can also create additional problems. Furthermore, this approach creates other problems for the prosthetic user, because it is often difficult to add or subtract stump socks when the need may arise. Obviously, this requires a private environment, and an individual must remove the prosthesis and add or remove stump socks and put the artificial limb back on. Access to privacy is unavailable much of the time during the day for some people, and carrying a supply of various prosthetic socks is also cumbersome and inconvenient.
There has, therefore, been a continual and long felt need for an adjustable system that does not rely on stump socks or visits to the prosthetist for adjustments to compensate for fitting problems.
One approach that has been seen in the field and described in certain patent literature utilizes an air system, with the principle of using air as an interface between the residual limb and the socket in an attempt to increase the comfort of ambulating with an artificial limb. However, for the amputee to simply put on an air sock and pump it up with air and expect it to be usable is an unreaslistic expectation. One reason why this simple broad approach to date has been unworkable is that it does not provide for rotational stability which is a must if the amputee is to control his prosthesis. It is essential, with this type of approach that the socket must have a contoured interface that closely matches the contours of the amputation, if stability is to take place. Nothing can replace the expertise of the prosthetist in determining where the best placement for file weight bearing areas will be on a wide variety of below-knee amputees.
Others in the field have suggested an inflatable pad or bladder, which allows the amputee to put an air pad into the socket and inflate it with air pressure. This system, however, is wanting in that there is only a small area to be effected by the air pad. Inflating the pad could cause too much pressure on the opposite side of the residual limb where the pad is not worn, since inflating the pad means squeezing the residual limb to the other side of the socket.
In the system of the present invention., an air bladder is used in which it becomes part of an integrated prosthetic socket designed by the prosthetist. The weight bearing areas are determined by the prosthetist by forming selected openings or holes through the inner socket wall, with the location of the openings as well as the size being made by the prosthetist to suit the needs of the amputee. This as will be shown allows the amputee to inflate or deflate the bladder and adjust the fit to their individual needs. Thousands of prosthetic devices are replaced each year because they no longer can be adjusted as to fit. It will be seen that the socket system of the present invention allows the amputee to adjust the socket for personal comfort in order to provide the proper pressure and the proper weight bearing locations against the residual stump to control the movement and rotational stability of the prosthetic appliance.